The Unique Nikkor-O CRT 55mm f/1.2 Lens

[Michael Erlewine]

Using the very helpful lens-tester on CoinImaging.com:

http://coinimaging.com/macro_lens_tests.html?

I was able to test a number of lenses that I often use for close-up photography. The lenses I am looking at here include:

Nikkor-O CRT 55mm f/1.2 Lens
Nikon APO-El-Nikkor 105mm f/5.6
Nikon Printing-Nikkor APO 150mm f/2.8
Schneider MacroVaron 85mm f/4.5

These are four of the best industrial lenses that I know of. Most of you probably know of all these lenses. But something I did not know, although I sensed it, was the uniqueness of Nikkor-O CRT 55mm f/1.2 Lens, not just because of its curvature as used in monitoring CRTs, but how incredibly sharp and good it is at resolving images. I think it is best to just look at these charts. You should be able to see which colored line goes with which lens. They tell the whole story. The CRT Nikkor-O is the dark-blue line.

I would be interested in your remarks.

[Bjørn Rørslett]

The qualities of the Nikkor-O CRT 55/1.2 have  been known for a long time. Nice to see charts corroborating that impression too. The caveat of course being the CRT is not a "white light" design, thus its performance might to some extent depend on the spectral range of light for which it is deployed. Also it flares quite easily under outdoor shooting so using say a K-4 tube as a make-shift lens hood is highly recommended.

I wonder about the actual graph for effective aperture though. The 55/1.2 is optimised for around 1:4.4 - 1:5, which is difficult to achieve for a DSLR system and we often end up at 1:3 or thereabouts. Still the maximum effective aperture would then not drop below f/1.6 (approx.) even in this case. The chart indicates a starting point at f/5??

[Akira]

If you mount the Nikkor-O onto the F-mount camera only via BR-15, you can get close to 1:5.  Idealistically, you want to remove the accompanying retaining ring, but, in that case, the end of the long L39 thread interferes with the aperture control lever of the body.  Ironically, you can mount the lens onto a Canon body without the retaining ring via BR-15 and F to EOS adapter, you can achieve 1:5 magnification thanks to the absence of the aperture control lever of EOS bodies.

[Bjørn Rørslett]

Even with the dedicated BR-15, one hardly gets into the design range 1:4.4-1:5 and there is a real risk of damaging the internal levers in the camera throat as well. I'm using a slightly thicker adapter (based on an F-C adapter, modified to give room for a CPU - surprise??) and ends up around 1:3 or so. Not perfect, but acceptable in terms of performance I'd guess. The retaining nut has to be removed of course otherwise the lens cannot be seated 'deep' enough.

The reversed lens could get me to 5:1, but then the setup with a Mitutoyo metallurgical objective and the Raynox DCR-150 is more practical at least for the purposes of interest for me.

[Akira]

Bjørn, I wouldn't be surprised if you add the chip even to Nikkor-O.  I'm immune enough. 

I once tried 5:1 with Nikkor-O, but the extension was too long (30+ cm) to stabilize the whole rig unless the rig is directed straight downward.

[Michael Erlewine]

While we are talking about this exotic lenses, I have a question for Bjørn:

I have studied a lot of folks who review and write about lenses, but have learned most from your early (and continued) work. If you know, what in your opinion are the best corrected, sharpest, best resolving (and preferably fast) lenses for non-macro magnification, like 0.25 through 1.0?

Any ideas would be helpful. Thanks.

[Bjørn Rørslett]

You have it already in your arsenal: CV 125/2.5 APO.

[Michael Erlewine]

You have it already in your arsenal: CV 125/2.5 APO.

Yep, I do. It is still the best all-around close-up/macro lens I know of and it is good to infinity as well. Just wondering about whether there are others you suggest.

How about all the many, many 55mm lenses from Nikon. Which of all of those is closest to what I am looking for, in your opinion?

[F2F3F6]

It seems that this 1,2/55 Nikkor O and the fabulous 5,6/105 Apo EL are the best for "low" magnifications between 0,2 (1;5) and 0,5x (1:2)...Just what you're looking for your wonderful flower works, Michael if I'm right ?

But if you compare them with the 4/45 Schneider apo-componon lens (sharpness vs magnification or resolution vs magnification) it seems that lens is "better" from 0,7x to 3x ?

At 0,5x the micro-Nikkor 2,8/55 Ais seems also a winner : in the "lens hall of fame" it has a better rank than 1,2/55 O or 5,6/105 apo EL...(sharpness, resolution and corner sharpness)...

These charts (sharpness vs magnification / resolution vs magnification) are made at the best aperture of the lens ? But best aperture changes with magnification, if I'm right (diffraction...).

So if I can't find a 1,2/55 O or 5,6/105 Apo EL, seems that I can do it with Micro-Nikkors or find an Apo Componon 4/45 (easy to find and much cheaper).

Would like to see a comparison between the legendary Apo EL-Nikkors 105/150 mm and other (moderns) Apo Componons or Apo-Rodagons...(4/80, 4,5/90, 4/105 and 4/150).

[richardHaw]

i hope there's a native F-mount  version made 

[Bjørn Rørslett]

For the CRT 55/1.2, yes there was the "Oscilloscope-Nikkor", an older version with [probably] the same specifications. I have seen advertising photos of it mounted onto a Nikon F. Never seen this version in the wild though.

Even with the CRT 55/1.2 you can easily adapt it to an F-mount by using the BR-15 adapter. Experiment a little how far lens can be seated into the adapter, as modern cameras obviously have less clearance in the camera throat. Maximum compatibility with the design parameters is achieved by removing the 39 mm thread nut, however you have to be very careful about the distance that the rear end of the lens protrudes into the camera throat.

[Akira]

For the CRT 55/1.2, yes there was the "Oscilloscope-Nikkor", an older version with [probably] the same specifications. I have seen advertising photos of it mounted onto a Nikon F. Never seen this version in the wild though.

Even with the CRT 55/1.2 you can easily adapt it to an F-mount by using the BR-15 adapter. Experiment a little how far lens can be seated into the adapter, as modern cameras obviously have less clearance in the camera throat. Maximum compatibility with the design parameters is achieved by removing the 39 mm thread nut, however you have to be very careful about the distance that the rear end of the lens protrudes into the camera throat.

Maybe our Lens Doctor would trim the L39 thread?    Apparently the thread part can be removed easily, and the trimming of it by 1.5-2.0mm would be enough to avoid the interference with the aperture control lever of the body.

[Bjørn Rørslett]

One will not need to remove the long end with the 39 mm threads. Although this part apparently can be removed, it serves no positive purpose as this doubles as the casing for the rear elements. However that being said, I examined my sample of the CRT 55 and removing approx 2 mm of the bezel at the end should be easy (for Erik Lund aka 'Dr. Lens' ,  not easy for me or other mere mortals as one works perilously close to the surface of the rear element). Concomitantly the BR-15 probably requires some modification to allow seating the lens a tad deeper. Again, a feasible task with the same caveat.

Still a lot of work to move the lens a little closer to its designated conjugate distance for maximal performance.

[richardHaw]

For the CRT 55/1.2, yes there was the "Oscilloscope-Nikkor", an older version with [probably] the same specifications. I have seen advertising photos of it mounted onto a Nikon F. Never seen this version in the wild though.

Even with the CRT 55/1.2 you can easily adapt it to an F-mount by using the BR-15 adapter. Experiment a little how far lens can be seated into the adapter, as modern cameras obviously have less clearance in the camera throat. Maximum compatibility with the design parameters is achieved by removing the 39 mm thread nut, however you have to be very careful about the distance that the rear end of the lens protrudes into the camera throat.

Thanks! the ones for sale are still around the $1,500.00 mark 

[Michael Erlewine]

Thanks! the ones for sale are still around the $1,500.00 mark 

I have one CRT-Nikkor (latest version) that I might part with if anyone is interested. ($950 plus shipping)